The present invention refers to an ophthalmic surgical device for macerating the lens nucleus (cataract) in the eye as well as aspirating of particulate lens nucleus from the eye of a living being. In particular, the present invention is concerned with an ophthalmic surgical device of the type essentially including a housing in form of a handpiece that has a head piece for receiving a guide tube which coaxially supports a tubular probe. A drive mechanism is arranged within the housing for rotating about the longitudinal axis of the guide tube a cutting element which is supplied with irrigation fluid from an infusion conduit, with excess fluid being withdrawn together with lens particles by a suction pump via the tubular probe and via a suction line which is connected to the vacuum pump.
The lens (ocular) is part of the optical eye system of a living being. The primary function of the lens is the adjusting ability of the refractive power, i.e. the accommodation of the eye for close objects. The accommodation which is attained essentially by the zonule fibers in cooperation with the ciliary muscle to essentially modify the ellipsoid configuration of the lens is dependent from the constitution (flexibility) of the lens nucleus.
When the lens nucleus becomes clouded and/or sclerosed, a disease known as so-called gray cataract, the vision becomes significantly impaired. Cataracts are differentiated essentially between congenital cataracts or cataracts caused by trauma, disease, or age. Senile cataracts which may occur between ages 50 and 60 are characterized by the accumulation of metabolic products within the lens fibers and by a disturbance between the osmotic balance of the lens and the aqueous humor. Vision impairing opacity of the eye may also occur following ocular trauma through accidents or those associated with systemic diseases such as diabetes mellitus and scleroderma. In general, a cataract is removed by employing intracapsular extraction by which the clouded lens is completely removed and subsequently replaced by an artificial implant.
U.S. Pat. No. 4,320,761 discloses a surgical device for excision of tissue, in particular for removing the gray cataract from the eye of a living being. The surgical device includes essentially a housing which accommodates a D.C. motor powered by a D.C. battery. Threadably engaged to the housing is a head piece which receives a first hollow needle communicating with a suction pump. Secured in side-by-side relation to the first needle is a second needle which is connected to a source of irrigation fluid. A shaft driven by the motor extends through the first needle and terminates in a twisted cutting tool by which the cataract to be removed is comminuted while simultaneously introducing a washing fluid and discharged together with excess washing fluid.
German patent no. DE-A 4,080,594 describes an ophthalmic surgical instrument for comminuting and removing lens debris and includes a hand-held housing which supports a receptacle in operative connection with suitable drive means. Received in the receptacle is a hollow needle formed as an ultrasonic probe with a lumen connected with a suction line via a passageway traversing the receptacle. The hollow needle or ultrasonic probe is moved longitudinally exclusively at high frequency while at a same time a washing fluid is supplied via an annular channel to the forward end part of the ultrasonic probe which is provided with outlet openings. The washing fluid is withdrawn and removed together with lens debris via the lumen of the hollow needle from the anterior chamber of the eye.
Further ophthalmic surgical instruments in form of rotary drills for comminuting a lens nucleus and for removing lens debris are further known from U.S. Pat. Nos. 3,976,077 and 4,002,169.